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Species in the beetle family Histeridae exhibit numerous defensive adaptations, from a generally compact and spheroid body shape to retractable tarsi, legs, heads, and antennae. Modes of antennal concealment are particularly variable, underscoring the importance of protecting these essential sensory structures. Understanding the evolution of these morphological features has been hindered by a weak understanding of the family's basal phylogeny, and corresponding patterns of niche-use and morphological evolution. Cretaceous amber fossils have been proliferating, filling in important morphological gaps right around the time of the family's explosive radiation. Here we describe 10 new species from Cretaceous Burmese ambers, six of them representing new genera: Palaeabraeus glabrus gen. nov. et sp. nov. (Abraeinae); Pseudacritus extinctus gen. nov. et sp. nov. (Abraeinae); Miculissima excavata gen. nov. et sp. nov. (unplaced to subfamily); Placatister cascus gen. nov. et sp. nov. (unplaced to subfamily); Cretomalus tibiodentatus gen. nov. et sp. nov. (Dendrophilinae: Paromalini); Prodigister tricostatus gen. nov. et sp. nov. (unplaced to subfamily); Anapleus punctulatus sp. nov. (Dendrophilinae: Anapleini); Pantostictus hirsutus sp. nov. (Abraeinae: Pantostictini); Phasmister kraliceki sp. nov. (Onthophilinae); and Phasmister planatus sp. nov. (Onthophilinae). A revised phylogenetic analysis that includes these taxa supports previous hints that inquilinous forms were prevalent and diverse during the Cretaceous. These results also support the contention that pressures in these environments to protect the critically important sensory apparatus, the antenna, were strong, driving multiple origins of two of the more protective configurations among extant taxa. Some of the new genera remain unplaced to subfamily, underscoring the gaps that still remain in the early fossil record for the family, and the continued need for more comprehensive analyses of combined data from extant taxa, along with additional extinct forms that we may assume will continue to be discovered. [ABSTRACT FROM AUTHOR]

DNA-based studies have revealed that the terrestrial water scavenger beetle genus Cercyon Leach, 1817 (Coleoptera: Hydrophilidae: Sphaeridiinae: Megasternini) is polyphyletic, grouping similarly looking but unrelated species that were not assigned to other genera due to the absence of unusual morphological characters. In this study, we analyse the morphology, DNA data and species diversity of one of the Asian clades of ' Cercyon ' to test whether a natural, phylogeny-based generic classification can be established. We add DNA data (five nuclear and three mitochondrial fragments) for additional species and specimens of the clade to test its monophyly and reveal phylogenetic relationships among species. We perform a detailed morphological study of all species, including SEM micrographs, to reveal synapomorphies of the DNA-based clades. We demonstrate that the lineage, described here as Asiacyon Mai, Jia, Ryndevich & Fikáček, gen. nov., is strongly supported by DNA data, has limited distribution (eastern Asia), and its species share similar biology (inhabiting fresh or decaying plant tissues), though it can be only diagnosed by a combination of plesiomorphic characters. A detailed treatment is provided for the Chinese species, including species diagnoses, illustrations of habitus and male genitalia, (re)descriptions and a key to species. A total of 14 Chinese species are recognised, of which 11 are described as new: Asiacyon pax sp. nov. (Guangdong, Hong Kong, Hunan), A. pseudincretus sp. nov. (Anhui, Jiangxi, Taiwan, Zhejiang), A. vicincretus sp. nov. (Guangdong, Guangxi), A. zhengyucheni sp. nov. (Yunnan), A. huilanae sp. nov. (Yunnan), A. cornipenis sp. nov. (Yunnan), A. belousovi sp. nov. (Yunnan), A. liangchengi sp. nov. (Yunnan), A. paraequalis sp. nov. (Yunnan), A. pengzhongi sp. nov. (Hunan) and A. xiuzhenae sp. nov. (Hainan, Yunnan). Three Chinese species previously classified in Cercyon are transferred to Asiacyon : A. incretus (d'Orchymont, 1941), comb. nov., A. primoricus (Ryndevich & Prokin, 2017), comb. nov. (newly recorded from China) and A. indicus (d'Orchymont, 1926), comb. nov. (newly recorded from China and Laos). Additionally, seven Asian species previously classified in Cercyon are transferred to Asiacyon based on their external morphology, but not studied in detail: A. aequalis (Sharp, 1884), comb. nov., A. conjiciens (Walker, 1858), comb. nov., A. dilutus (Régimbart, 1903), comb. nov., A. placidus (Sharp, 1884), comb. nov., A. pseudodilutus (Satô, 1979), comb. nov., A. retius (Ryndevich & Prokin, 2017), comb. nov., and A. rubicundus (Sharp, 1884), comb. nov. In total, the genus now comprises 21 named species and several undescribed species from India, Myanmar and Indonesia. ZooBank: Morphology is not always a good indicator of biological diversity, aswe illustrate in Asian species classified under Cercyon , a genus of terrestrial water scavenger beetles. We describe Asiacyon gen. nov., which is strongly supported by DNA data, has limited distribution and unique habitat preferences, yet it highly resembles other unrelated ʻ Cercyon ʼ. The species diversity of this lineage was under-estimated: we describe 11 new species from China. We argue that ' Cercyon ' should be divided into DNA-based natural genera despite their morphological similarity. (Image credit: Martin Fikáček.) [ABSTRACT FROM AUTHOR]

South Pacific archipelagos are central in the biogeographic debate on the relative importance of vicariance and dispersal in shaping the distribution of species. However, each taxonomic group was subject to different processes and histories, and here, we reveal the historical biogeography of the diverse Eumolpinae leaf beetles, widely distributed in the region. Extensive taxon sampling focusing on South Pacific Eumolpinae was used to infer the first molecular phylogeny of the group using three single‐copy protein‐coding nuclear and two mitochondrial markers. Upon assessing the clade of interest for lineage‐specific variation in substitution rates, the age of the most recent common ancestors was estimated using out‐group calibration and multi‐gamma site models (MGSMs). Biogeographic analyses used standard event‐based inferences also incorporating phylogenetic uncertainty. Zealandian Eumolpinae are monophyletic and appear to have split from their global relatives in the transition from the Cretaceous to the Paleogene. Variation in the rates of molecular evolution affected the in‐group stem branch, with a significant drop in the substitution rate, and the MGSM correction recovered the crown age of Zealandian Eumolpinae during the Late Eocene–Oligocene transition. Biogeographic inference resolved the origin of the radiation in New Caledonia, favouring a null model without island age constraints, and repeated dispersal events to the other islands, including three independent but synchronous colonisations of New Zealand during the Miocene. New Caledonia, with a highly diverse Eumolpinae fauna of uncertain origin, acted as a hub and pump of biodiversity of these beetles in the entire South Pacific region, sending migrants to other islands through long‐distance dispersal with lineages establishing when land became available. [ABSTRACT FROM AUTHOR]

The turbulent Tertiary and Quaternary history of Europe and the Ponto-Caucasus has had a strong impact on its biota, resulting in unusual patterns of speciation, diversification, and dispersal. Our study reveals the Late-Tertiary diversification and biogeographic history of Mniophila , a Western Palaearctic endemic moss-inhabiting flightless flea beetle distributed across Europe and the Ponto-Caucasus. We assembled samples across the whole range of the genus except Crimea. Based on a molecular phylogenetic analysis, we found that the diversification of Mniophila started in the Balkan Peninsula, and was followed by at least two independent colonizations of other parts of Europe. The Ponto-Caucasian species are all descendants of a single colonization from the Balkans, followed by species' radiation. The Mniophila beetles are, therefore, one of the first-known cases of the colonization of the Caucasus from Europe. We integrated our DNA data with morphology, allowing us to uncover the cryptic diversity of Mniophila and to revise its European species. We describe Mniophila haveli sp. nov. from the Carpathians and Balkans, M. wroblewskii Wańkowicz, 1880 from Central Europe and the Balkans is restored as a valid species, and M. bosnica Apfelbeck, 1914 is newly recognized as a Dinaric endemic. We reveal an exceedingly large distribution range for M. muscorum (Koch, 1803), which is unusual for a flightless beetle. [ABSTRACT FROM AUTHOR]

Forest soil and leaf litter support diverse arthropod mesofauna for which diversity dynamics is challenging to study due to the high number of species and specimens, small body size and limited taxonomic knowledge.Immature stages (larvae) are even harder to identify than adults, as their morphology is largely unknown. Therefore, larvae are often ignored, even though they may form a substantial proportion of specimens collected, are less mobile than adults and their exclusion may provide an incomplete diversity profile.Here, we use Oxford Nanopore DNA barcoding to investigate whether the inclusion of larvae provides a more complete taxonomic, phylogenetic and functional diversity profiles in leaf litter beetles (Coleoptera) from a subtropical forest in Taiwan.Our results indicate that larvae represent up to 38% of beetle specimens per sample, but most of them belong to 2–3 common species. Larvae of most beetle species are rarely collected repeatedly or in multiple specimens, possibly due to special habitat requirements or high seasonality.Taxonomic, phylogenetic and incidence‐based functional diversity measures were not affected by the exclusion of larvae in the Staphylinidae dataset but were strongly biased in all‐beetle dataset, especially when only common or abundant species were considered. Taxonomic beta diversity was not affected by the omission of larvae.Our results indicate that immature stages may be omitted in ecological studies of arthropods in case both adults and larvae co‐occur in the same habitat, and the sites are sampled repeatedly. Caution is needed (1) in groups in which larvae and adults do not inhabit the same environment or strongly differ in biology, (2) when rare species are omitted or (3) when functional diversity is calculated from abundance data. [ABSTRACT FROM AUTHOR]

Aim: Although Antarctica hosted a diverse fauna and flora in the past, its modern climate is too extreme for many lineages: their recent extinction makes it difficult to include the continent in historical biogeographical analyses. We use southern temperate stream‐inhabiting beetles as a model to explore whether Antarctica may be included in historical biogeographic reconstructions in a group absent from Antarctica today, and to test its role in shaping the current distribution of stream‐inhabiting insects. Taxon: Coleoptera, Elmidae. Location: Southern Hemisphere temperate regions and Antarctica. Methods: We included Antarctica in historical biogeographic analyses indirectly, as a component of distance matrices specifying the relative positions of continents, or by specifying Antarctica as a stepping‐stone between remaining continents (in LEMAD). We used a newly constructed dated phylogeny of Elmidae to test the performance of these constrained analyses under different parameter settings and geographical scenarios. Results: Antarctica can be implemented into historical biogeographic analyses via indirect constraints to produce biologically relevant reconstructions when long‐distance dispersal events are highly penalized, the maximum number of areas per species is low, and expected extinction rates are high (in LEMAD). Unconstrained models, including those without Antarctica, result in simpler scenarios with fewer biogeographic events and better fit to data. The origin of austral clades of Elmidae post‐date the separation of Gondwanan landmasses. Main Conclusions: Antarctica can be included in historical biogeographic reconstructions under a priori assumptions that (1) it was part of the ancient biogeography of the clade, (2) the taxon has limited dispersal ability, making long‐distance dispersal highly unlikely and (3) maximum range size is limited. These assumptions may be biologically justified for many animal groups. Over‐water dispersal has been crucial in shaping the modern distribution of austral stream‐inhabiting beetles, likely facilitated by ocean currents and dispersal through Antarctica until the Oligocene. [ABSTRACT FROM AUTHOR]

Army ants provide nourishment to a large variety of animals. This includes birds that feed on animals flushed out by army ant raids, symbiotic arthropods that consume the ants' prey or their brood, and other arthropods that scavenge on army ant refuse deposits. The latter have not received much attention, and the few published studies lack detailed species identifications. Here we provide a first systematic inventory of the beetle fauna associated with refuse deposits of Eciton army ants, with a focus on Eciton burchellii. We collected 8364 adult beetles, 511 larvae, and 24 eggs from 34 deposits at La Selva Biological Station, Costa Rica. We used a combination of DNA barcoding and morphology to identify a subset of 436 specimens to species level. The samples included several new species, and we here formally describe two water scavenger beetles (Hydrophilidae). Refuse deposits harbored a diverse beetle fauna. The identified subset consisted of 91 beetle species from 12 families, with rove beetles being the most abundant and diverse visitors. Of the 85 species found with E. burchellii, 50 species were collected from only one or two refuse deposits. Conversely, seven species were found in 10 or more refuse deposits, indicating a certain level of habitat specialization. We matched adults and immatures for 22 beetle species via DNA barcodes, demonstrating that army ant middens also serve as a beetle nursery. The present survey highlights the significant ecological function of army ants as promoters of biodiversity and their status as keystone species in tropical rainforests. [ABSTRACT FROM AUTHOR]

The larval morphology of Crephelochares Kuwert, 1890 and Peltochares Régimbart, 1907 is described in detail based on specimens of C. abnormalis (Sharp, 1890) and P. atropiceus (Régimbart, 1903) collected in Taiwan; the chaetotaxy of the head capsule and head appendages of both genera is described for the first time. Larvae were obtained by laboratory rearing and field collecting; field collected larvae were identified by morphological comparison with those reared in the laboratory. Larval morphology of C. abnormalis corresponds with that of C. nitescens (Fauvel, 1883) except for the serrate margin of the nasale in C. abnormalis. We confirm that Crephelochares does not construct the usual egg case, and report active behaviour of its larvae, possibly indicating they are not ambush predators. Larval morphology of P. atropiceus corresponds with that of P. foveicollis; on the other hand, we conclude that the larvae previously described as Peltochares from Madagascar belong to Tritonus Mulsant, 1844 of the tribe Laccobiini. The egg-carrying behaviour of Peltochares is confirmed. We briefly summarize the state of the knowledge of immature stages of the Acidocerinae, indicating that a special effort in discovering and describing immature stages from northern South America and Brazil is needed. [ABSTRACT FROM AUTHOR]

Systematic bias is one of the major phylogenetic issues arising over the last two decades. Using methods designed to reduce compositional and rate heterogeneity, hence systematic bias, Cai and co‐workers (2022) (= CEA22) reanalyzed the DNA sequence dataset for Coleoptera of Zhang et al. (2018) (= ZEA). CEA22 suggest that their phylogenetic results and major evolutionary hypotheses about the Coleoptera should be favoured over other recently published studies. Here, we discuss the methodology of CEA22 with particular attention to how their perfunctory reanalysis of ZEA obfuscates rather than illuminates beetle phylogeny. Similar to published rebuttals of an earlier study of theirs, we specifically find that many of their claims are misleading, unsupported, or false. Critically, CEA22 fail to establish the stated premise for their reanalysis. They fail to demonstrate how composition or rate heterogeneity supposedly impacted the phylogeny estimate of ZEA, let alone the results of other recent studies. Moreover, despite their claim of comprehensive sampling of Coleoptera, their dataset is neither the most diverse with respect to species and higher taxa included, nor anywhere near the largest in terms of sequence data and sampled loci. Although CEA22 does contribute additional fossils for calibration, those seeking the best available estimate for Coleoptera phylogeny and evolution based on molecular data are advised to look elsewhere. [ABSTRACT FROM AUTHOR]

Sphaeriusidae (Coleoptera: Myxophaga) is a group of shiny, blackish and hemispherical riparian beetles, known for their miniaturized bodies. They are worldwide in distribution, but very limited information is available about taxonomic and morphological diversity, and natural and evolutionary history. The aim of this study is to help fill in these gaps. We examined the external morphology of modern representatives using scanning electron microscopy (SEM), and reconstructed the phylogeny of the family using five DNA markers (cytochrome oxidase I, 18S rRNA, 28S rRNA, CAD and wingless). Our results suggest a larger morphological diversity than previously expected, corresponding to the deep genetic divergences of principal lineages. We also examined two inclusions in 99‐million‐year‐old Burmese amber. The integration of all evidence allows us to recognize three genera: the extinct genus †Burmasporum Kirejtshuk, the newly defined genus Bezesporumgen.nov. preserved in Burmese amber (B. burmiticumsp.nov.) and present in the modern fauna of Southeast Asia, and the genus Sphaerius Waltl with a world‐wide distribution. Sphaerius species are morphologically highly uniform, with the exception of species from Australia and South Africa, which share some characteristics with Bezesporumgen.nov. despite being resolved as deeply nested lineages of Sphaerius by DNA data. The presence of Bezesporumgen.nov. in Burmese amber and in recent fauna indicates that Sphaeriusidae largely maintained their specific morphology and specialized riparian lifestyle for at least 100 million years. Therefore, they can be considered an exceptionally conserved group, with a minimum of evolutionary changes over a long period. Our study also demonstrates that the species numbers and fine‐scale morphological diversity of Sphaeriusidae are larger than expected in both the past and present‐day faunas. Both were apparently underestimated due to the minute body size and cryptic habits of these beetles. [ABSTRACT FROM AUTHOR]

The family Cerasommatidiidae was proposed by Brèthes in 1925 for his new genus Cerasommatidia from Brazil, described as an intermediate taxon between Endomychidae and Coccinellidae (Coccinelloidea). This group was neglected for decades until 1994 when the resemblance of Cerasommatidia with the eupsilobiine genus Ibicarella was noticed, and Cerasommatidiidae was synonymized with Eupsilobiinae (Endomychidae). Based on the newly discovered material from the Neotropical and Afrotropical regions with clear resemblance to Cerasommatidia and Ibicarella , the phylogenetic placement of these taxa and new allied genera was reassessed based on phylogenetic analyses of molecular, morphological and combined datasets. The data were analysed under Bayesian (BI), maximum likelihood (ML) and parsimony (MP) frameworks. Our results support the restoration of Cerasommatidiidae as a distinct family in Coccinelloidea. Close affinity of Cerasommatidiidae with Coccinellidae, Eupsilobiidae and Mycetaeidae is recovered and the sister-relationship to Mycetaeidae is highly supported. Ibicarella is found to be a junior synonym of Cerasommatidia. Three new genera and six new species are described and illustrated: Yamuy gen. nov. (type species, Y. marginatus sp. nov. ; and Y. constratus sp. nov.) and Karumbe gen. nov. (type species, K. geiseri sp. nov. ; K. brethesi sp. nov. and K. pakaluki sp. nov.) from the Neotropics and Mahavelo gen. nov. (type species, M. madagasus sp. nov.) from Madagascar. [ABSTRACT FROM AUTHOR]

Flea beetles (Alticini) are a diverse lineage of leaf beetles (Coleoptera: Chrysomelidae) with the majority of genera living on vascular plants. However, several genera are associated with mosses or leaf litter, as an alternative strategy, often accompanied by changes in morphology and biology. Here, we present the first comprehensive DNA-based phylogenetic analysis of Alticini including 13 moss-inhabiting genera. We show that moss-association is a common phenomenon in Alticini; based on our ancestral-state mapping, we reveal at least nine independent origins of moss-inhabiting, and four independent origins of leaf-litter-inhabiting life-strategy. Our findings illustrate that both cryptic strategies induce parallel evolution of similar ecomorphological adaptations, such as flight loss and a convex body shape. An overview of known moss-inhabiting flea beetle genera is also provided. We describe Benedictoides munclingeri gen. et sp. nov. from the cloud forests of Mount Cameroon, the first flea beetle genus clearly assigned to the moss-inhabiting strategy from tropical Africa. Additionally, our phylogeny provides new insights into the relationships among various flea beetle genera. We estimate six main clades grouping the majority of studied genera, and propose several new generic groups. Along with our phylogenetic results, we discuss moss-inhabiting flea beetle evolution and perspectives of their systematics. [ABSTRACT FROM AUTHOR]

Moss‐inhabiting flea beetles form a very diverse and understudied ecological group of leaf beetles (Coleoptera: Chrysomelidae) characterized by cryptic lifestyle, loss of flight ability and feeding on mosses as both adults and larvae. We present the first DNA‐based study of the phylogenetic position of moss‐inhabiting flea beetle genera Ivalia Jacoby and Cangshanaltica Konstantinov et al., based on sequences of two mitochondrial and three nuclear genes. We confirm that both genera are members of the monophyletic Chabria group, along with Chabria Jacoby, Parathrylea Duvivier, Chabriosoma Chen and Sutrea Baly. Moss‐inhabiting species form at least three independent lineages within the Chabria group, indicating multiple parallel origin of the association with mosses within the clade. We reveal the monophyly of Cangshanaltica and confirm its separate generic status from Ivalia. Ivalia is revealed as polyphyletic, consisting of at least two unrelated moss‐inhabiting lineages. In contrast, the externally similar moss‐ and leaf‐litter inhabiting genera Mniophila Stephens, Adamastoraltica Biondi et al. and Clavicornaltica Scherer are not closely related to the Chabria group. Our study specifically focused on the moss‐inhabiting flea beetles of Taiwan. We reveal that the Taiwanese fauna is a result of four independent colonizations of the island: one from China (Cangshanaltica) and three from the Philippines (three lineages morphologically assigned to Ivalia). Two of these lineages (Cangshanaltica and the core Ivalia) radiated in Taiwan and gave rise to the majority of modern Taiwanese species. The evolutionary history of Cangshanaltica and its diversification in China are also discussed. [ABSTRACT FROM AUTHOR]

Larvae of water scavenger beetles (Coleoptera: Hydrophiloidea) are adapted to a wide variety of aquatic habitats, but little is known about functional and evolutionary aspects of these adaptations. We review the functional morphology and evolution of feeding strategies of larvae of the families Hydrophilidae and Epimetopidae based on a detailed scanning electron microscope (SEM) analysis, analysis of video records of feeding behaviour and observations of living larvae. There are two main types of feeding mechanisms: chewing and piercing-sucking. The character mapping using the latest phylogenetic hypothesis for Hydrophiloidea infers the chewing system as the ancestral condition. The piercing-sucking mechanism evolved at least four times independently: once in Epimetopidae (Epimetopus) and three times in Hydrophilidae (Berosini: Berosus + Hemiosus ; Laccobiini: Laccobius group; Hydrobiusini: Hybogralius). The piercing-sucking apparatus allows underwater extra-oral digestion and decreases the dependence of larvae on an aerial environment. A detailed study of the tracheal morphology of the piercing-sucking lineages reveals four independent origins of the apneustic respiratory system, all of them nested within lineages with piercing-sucking mouthparts. We conclude that piercing-sucking mouthparts represent a key innovation, which allows for the subsequent adaptation of the tracheal system, influences the diversification dynamics of the lineages and allows the shift to new adaptive zones. [ABSTRACT FROM AUTHOR]

Water scavenger beetles (Coleoptera: Hydrophilidae) are a broadly distributed group with high extant diversity. However, reliable records from Baltic amber (Eocene) are scarce and limited to two undescribed species previously reported in the literature. Here we study these two specimens plus four additional ones. All specimens were sub-optimal in terms of preservation and visibility of their morphology using traditional light microscopy. Opaque bubbles, cracks in the amber pieces and contracted appendages obscured most of the crucial characters, preventing their formal description and making them prone to misidentification. Here we used X-ray micro-computed tomography (μCT) to reconstruct the morphology of the embedded specimens and described three new species: Anacaena morla sp. nov., Crenitis profechuyi sp. nov. and Helochares fog sp. nov. Micro-CT reconstructions allowed us to visualise the morphology of the specimens to an extent where it was possible to hypothesise possible phylogenetic relations of the new taxa as well as the biogeographic implications of these relationships. [ABSTRACT FROM AUTHOR]

This study summarizes available data on karyotypes of water scavenger beetles (Coleoptera: Hydrophiloidea: Hydrophilidae), based on newly acquired data of 23 genera and 64 species. We combine these data with previously published data, which we review. In total, karyotypes are available for 33 genera and 95 species, covering all subfamilies and tribes. Available data indicate that most groups of the Hydrophilidae are diploid and sexually reproducing, with XY (♂) and XX (♀) sex chromosomes; the Y chromosome is always minute and does not recombine with X during meiosis. Exceptions are known in Anacaena , with parthenogenetic diploid or triploid populations in some species and sex chromosomes fused with autosomes in others. The diploid number of chromosomes is 2 n  = 18 in the subfamilies Acidocerinae, Chaetarthriinae, Enochrinae and Hydrophilinae. Variations are known in species of Anacaena and Berosus (both usually with 2 n  = 18) and in Hydrochara and Hydrophilus with an increased number of chromosomes (2 n  = 30). The number of chromosomes is increased in the subfamily Cylominae (2 n  = 24–30) and in all subclades of the subfamily Sphaeridiinae (2 n  = 22–32). We summarize protocols for obtaining chromosome slides used for this study and provide step-by-step guidelines to facilitate future cytogenetic studies. [ABSTRACT FROM AUTHOR]

Megasternini is the largest group of terrestrial water scavenger beetles (Coleoptera: Hydrophilidae) represented by ca. 600 described species distributed worldwide. The highest species diversity is known from tropical areas of all continents. In this study, we used sequences of eight gene regions (five nuclear and three mitochondrial) to investigate the phylogenetic relationships and historical biogeography of this group, implementing maximum likelihood (ML) and Bayesian topology inference, Bayesian divergence dating, ML‐based ancestral area estimation and Bayesian diversification analyses. Topology analyses reveal two main lineages of Megasternini characterized by the morphology of male genitalia and surrounding sclerites; these lineages are defined here as subtribes Megasternina Mulsant and Oosternina new subtribe. We identify 12 principal clades of Megasternini, three in Oosternina and nine in Megasternina. These clades group the taxa largely by their geographic distribution rather than morphology, indicating a parallel evolution of morphological characters. Genera Cercyon Leach, Oosternum Sharp, Cetiocyon Hansen, Australocyon Hansen and Pelosoma Mulsant were not recovered as monophyletic. Species of Cercyon, the most diverse genus in the tribe, are found in all principal clades in both subtribes. These results suggest a need for the reorganization of generic concepts in the tribe. The historical biogeography analysis reveals a series of parallel intercontinental dispersal events, including the colonization of South America by Australian members of Oosternina ca. 90 million years ago (mya) and at least five dispersal events between Asia and America ca. 63–55 mya via the Beringia land bridge. The timing of the Asia‐America faunal interchange corresponds to the hyperthermal climate of the Late Paleocene and Early Eocene that allowed the expansion of tropical and subtropical biomes towards polar regions. Diversification analyses revealed no effect of intercontinental dispersals on speciation or extinction rates and suggested a possible effect of declining global temperatures in the last 20 million years. [ABSTRACT FROM AUTHOR]

Phylogenetic analyses testing the monophyly of the tribe Hydrobiusini and the relationships among its genera are performed based on a data matrix including characters of larval morphology and morphometrics, larval chaetotaxy and adult morphology, including eight of the nine hydrobiusine genera plus 15 outgroup taxa. The head chaetotaxy of six genera of the tribe Hydrobiusini is described (Ametor , Hybogralius , Hydramara , Limnohydrobius , Limnoxenus and Sperchopsis). Morphometric characters derived from the head capsule and mouthparts are included. All characters are illustrated in detail. The analyses performed on the above datasets and their combinations reveal the monophyly of the Hydrobiusini except for Hybogralius , and reconstruct the internal topology of the tribe, largely corresponding to results of previous molecular analyses. Hybogralius groups with genera having larvae adapted to underwater feeding in all analyses. The position of the genus Tritonus within the Laccobiini is questioned by our analyses, which suggest a closer relationship with the tribes Hydrophilini or Hydrobiusini. Larval characters are revealed as highly homoplastic, with chaetotaxic characters performing slightly worse than usual larval morphology. Nonetheless, they are phylogenetically informative and useful for testing phylogenetic hypotheses resulting from analyses of molecules or adult morphology. A key to larvae of the genera of the Hydrobiusini is presented. [ABSTRACT FROM AUTHOR]

Epimetopidae are a small beetle family of the superfamily Hydrophiloidea, comprising 72 described species in three genera: the American Epimetopus Lacordaire, 1854 (56 species), Asian Eumetopus Balfour-Browne, 1949 (eight species) and African Eupotemus Ji & Jäch, 1998 (eight species, of which six are described as new here). In this study we illustrate and compare the adult morphology of all three genera and generate the first DNA sequences for Eumetopus and Eupotemus. The morphological data and sequences of four genes (cox1, 16S, 18S and 28S) are used to reconstruct phylogenetic relationships among genera. Both strongly support the monophyly of Epimetopidae, reveal Eumetopus as the earliest diverging taxon and Epimetopus + Eupotemus as a strongly supported clade with numerous synapomorphies. The reciprocal monophyly of Epimetopus and Eupotemus is strongly supported by DNA data but not in the morphological analysis which reveals Epimetopus paraphyletic. Eumetopus, despite being the earliest branching clade, is characterized by many unique derived structures, e.g. by the presence of the sperm pump in males (unique in Hydrophiloidea). The available data on the biology of Epimetopidae indicate that most species inhabit sandy to muddy margins of streams or rivers. Females of all three genera carry egg cases; Epimetopidae hence are one of three independent lineages of Hydrophiloidea in which this behavior evolved. Larvae are only known for Epimetopus and are characterized by morphological adaptations for feeding by piercing and sucking, a closed tracheal system and abdominal gills; larvae of Eumetopus and Eupotemus remain unknown and further research is needed to confirm whether they show the same adaptations as Epimetopus. The taxonomy of the African genus Eupotemus is revised, with six species described as new: E. bilobatus sp. nov. (Nigeria), E. cameroonensis sp. nov. (Cameroon), E. ophioglossus sp. nov. (Gabon, Togo), E. smithi sp. nov. (Côte d'Ivoire), E. taianus sp. nov. (Côte d'Ivoire) and E. uluguru sp. nov. (Tanzania). Eupotemus limicola Delève, 1967 is fixed as the type species of the genus according to ICZN (1999: Art. 70.3). New records of Eumetopus species are provided (E. acutimontis Ji & Jäch, 1998 from Vietnam, E. bullatus (Sharp, 1875) from India: Maharashtra, E. flavidulus (Sharp, 1890) from India: Maharashtra and Andhra Pradesh, E. maindroni (Régimbart, 1903) from India: Maharashtra and Gujarat, and E. weigeli Skale & Jäch, 2003 from India: Uttarakhand). The habitus of all species is illustrated. An updated checklist of the Epimetopus species is provided, and records of two specimens of the E. costatus group from Zambia and Saudi Arabia are considered to result from either accidental introductions or mislabelling. [ABSTRACT FROM AUTHOR]

The Philippine islands are one of the key biodiversity hotspots in the Indo-Pacific area. Knowledge of moss-inhabiting flea beetles (Coleoptera: Chrysomelidae: Alticinae), a diverse and ecologically and morphologically enigmatic group in the Philippines is described. Six species from the Philippines are recorded, belonging to three genera: Benedictus luzonicus Sprecher-Uebersax et al., 2009 (recorded from the Philippines previously), Ivalia antennata sp. nov., I. caligulata sp. nov. and I. postfasciata (Chen, 1934), comb. nov. (transferred from Chabria Jacoby, 1887), Cangshanaltica mindanaoensis sp. nov., and C. luzonica sp. nov. Cox1 barcode sequences of Ivalia antennata and Cangshanaltica mindanaoensis are presented. Biogeography and diversity of moss-inhabiting flea beetles in the Philippines are discussed. [ABSTRACT FROM AUTHOR]

The New Zealand endemic beetle genus Saphydrus Sharp, 1884 (Coleoptera : Hydrophilidae : Cylominae) is studied in order to understand its phylogenetic position, species-level systematics, biology and distribution, and to reveal reasons for its rarity. The first complete genus-level phylogeny of Cylominae based on two mitochondrial (cox1 , 16S) and two nuclear genes (18S, 28S) covering 18 of 19 genera of the subfamily reveals Saphydrus as an isolated lineage situated in a clade with Cylorygmus (South America), Relictorygmus (South Africa) and Eurygmus (Australia). DNA is used to associate two larval morphotypes with Saphydrus : one of them represents the larvae of S. suffusus Sharp, 1884; the other, characterised by unique characters of the head and prothorax morphology, is revealed as sister but not closely related to Saphydrus. It is described here as Enigmahydrus , gen. nov. with a single species, E. larvalis , sp. nov., whose adult stage remains unknown. Saphydrus includes five species, two of which (S. moeldnerae , sp. nov. and S. tanemahuta , sp. nov.) are described as new. Larvae of Enigmahydrus larvalis and Saphydrus suffusus are described and illustrated in detail based on DNA-identified specimens. Candidate larvae for Saphydrus obesus Sharp, 1884 and S. tanemahuta are illustrated and diagnosed. Specimen data are used to evaluate the range, altitudinal distribution, seasonality and population dynamics over time for all species. Strongly seasonal occurrence of adults combined with other factors (winter occurrence in S. obesus , occurrence at high altitudes in S. tanemahuta) is hypothesised as the primary reason of the rarity for Saphydrus species. By contrast, Enigmahydrus larvalis underwent a strong decline in population number and size since the 1970s and is currently known from a single, locally limited population; we propose the 'nationally threatened' status for this species. http://zoobank.org/urn:lsid:zoobank.org:pub:28D87163-29E8-418C-9380-262D3038023A The New Zealand fauna is highly endemic, with many species only known from their type series. Moreover, threat through habitat loss, agriculture, climate change and the introduction of alien species drive the decline of species including the little-known ones. Our study reports on the systematics and distribution of the hydrophilid genera Saphydrus and Enigmahydrus , gen. nov. and analyses whether their rare occurrence may be due to human impact. Morphology of adult and immature stages is studied in detail and the taxa are placed into a phylogenetic context. [ABSTRACT FROM AUTHOR]

The evolution of the coleopteran suborder Adephaga is discussed based on a robust phylogenetic background. Analyses of morphological characters yield results nearly identical to recent molecular phylogenies, with the highly specialized Gyrinidae placed as sister to the remaining families, which form two large, reciprocally monophyletic subunits, the aquatic Haliplidae + Dytiscoidea (Meruidae, Noteridae, Aspidytidae, Amphizoidae, Hygrobiidae, Dytiscidae) on one hand, and the terrestrial Geadephaga (Trachypachidae + Carabidae) on the other. The ancestral habitat of Adephaga, either terrestrial or aquatic, remains ambiguous. The former option would imply two or three independent invasions of aquatic habitats, with very different structural adaptations in larvae of Gyrinidae, Haliplidae and Dytiscoidea. [ABSTRACT FROM AUTHOR]

Hydroscaphidae is a small family of the beetle suborder Myxophaga comprising miniaturised aquatic beetles resembling some staphylinids. Surprisingly little is known about the taxonomy and biology of these beetles. In this study we present novel data based on freshly collected material of Hydroscapha LeConte, 1874, from Taiwan and Hong Kong. Morphology and DNA barcoding revealed two species: Taiwanese endemic H. takahashii Miwa, 1935, and H. shuihau, a new species, so far known only from Lantau Island of Hong Kong. Both species are (re)described, illustrated, and compared to the types of H. hunanensis Pu, 1948. Both species were found in algal mats in ephemeral hygropetric habitats; in two cases adults massed together with immature stages were observed. Larvae and pupae of H. takahashii were studied and illustrated using SEM and light microscopy. Comparisons of immature stages of Hydroscaphidae based on our new data and a detailed review of the literature reveals that principal differences between genera and species can be found in the modifications of the tracheal system both in larvae and pupae. Four larval instars were found in H. takahashii, corresponding to the number of instars known in the myxophagan family Torridincolidae. Based on our observations, we suggest that the minute body size of Hydroscapha may be one of the adaptations for colonising and exploiting ephemeral habitats. [ABSTRACT FROM AUTHOR]

Triassic fossils are rare but crucial for understanding the early evolution of large insect clades including beetles (Coleoptera). Their phylogenetic assignment is problematic because of fragmentary preservation, yet crucial for the correct use of the information they provide. Here an analysis is presented of the phylogenetic position of Leehermania prorova, the Late Triassic compressed fossil which was described and hitherto widely used as the oldest representative of Staphylinidae (rove beetles) in the suborder Polyphaga. By contrast with the intuitive character assessment made in the original description, a phylogenetic analysis of Leehermania is performed using an extensive morphological matrix of extant Coleoptera provided by the Beetle Tree of Life project, constrained in view of the latest relevant molecular phylogenies. As a result, Leehermania is identified as an extinct lineage within the beetle suborder Myxophaga, closest to the modern family Hydroscaphidae. Excluding Leehermania from Staphylinidae and placing it in Myxophaga amends erroneous assumptions about early diversification of rove beetles and enhances our views of the evolutionary history of Coleoptera. [ABSTRACT FROM AUTHOR]

The Old World genus Thysanarthria Orchymont, 1926 is reviewed taxonomically and compared to the related genus Chaetarthria Stephens, 1835. Chaetarthria is considered to consist of three groups differing in the morphology of male genitalia and surrounding sclerites: (1) large Old World Chaetarthria which seems to stand apart of the remaining groups, and (2) European Chaetarthria plus (3) American Chaetarthria which both share the male sternite 8 with a long median projection with Thysanarthria. The reduced mesal part of male sternite 9 is shared by European Chaetarthria and Thysanarthria, supporting their close relationship proposed by previous molecular analyses. Sixteen species are recognized within Thysanarthria which differ in the details of the morphology of the aedeagus illustrated for all species. Seven species are described as new: T. bifida sp. nov. (Thailand), T. cardamona sp. nov. (India: Kerala), T. chui sp. nov. (Taiwan), T. persica sp. nov. (southern Iran), T. saurahana sp. nov. (Nepal), T. trifida (Laos), and T. wadicola sp. nov. (Oman). New records are provided for T. ceylonensis Hebauer, 2001 (new to India: Madhya Pradesh), T. championi (Knisch, 1924) (new to Afghanistan, India: Arunachal Pradesh, China: Yunnan, and Myanmar), T. madurensis Hebauer, 2001 (new to Nepal and India: Kerala), and T. siamensis Hebauer, 2001 (new to India: Uttarkhand, Nepal and Laos). Chaetarthriomorphus sulcatus Chiesa, 1967 is revealed as a junior synonym of Chaetarthria championi Knisch, 1924, and lectotypes are designated for both these taxa. An undescribed species of the American group of Chaetarthria is recorded from Saudi Arabia either as an accidental introduction or due to mislabeling; the species is illustrated but not described. [ABSTRACT FROM AUTHOR]

We are reporting a recent discovery of Coelostoma (Lachnocoelostoma) thienemanni Orchymont, 1932 (Coleoptera: Hydrophilidae: Sphaeridiinae: Coelostomatini) from northern Vietnam, which represents the first record of the species since 1929 and its first record from continental Asia. The species is redescribed and illustrated, and transferred from the subgenus Holocoelostoma Mouchamps, 1958 to Lachnocoelostoma Mouchamps, 1958. The species is unusual among Asian Coelostoma by its complex three-dimensional shape of the median lobe of the aedeagus, in which it is only similar to C. tangliangi Jia et al., 2017 in Asia. The species is also unusual by its very long dorsal tarsal swimming hairs, indicating that it is an aquatic species. [ABSTRACT FROM AUTHOR]

Hydrophilidae (water scavenger beetles) is well known as an aquatic beetle family; however, it contains ca. 1,000 secondarily terrestrial species derived from aquatic ancestors. The New Zealand endemic genus Rygmodus White is a member of the hydrophilid subfamily Cylominae, which is the early-diverging taxon of the largest terrestrial lineage (Cylominae + Sphaeridiinae) within the Hydrophilidae. In this paper we report that Rygmodus beetles are pollen-feeding flower visitors as adults, but aquatic predators as larvae. Based on analyses of gut contents and a summary of collecting records reported on museum specimen labels, adult Rygmodus beetles are generalists feeding on pollen of at least 13 plant families. Rygmodus adult mouthparts differ from those of other (saprophagous) hydrophilid beetles in having the simple scoop- like apex and mola with roughly denticulate surface, resembling the morphology found in pollen-feeding staphylinid beetles. Larvae were found along the sides of streams, under stones and in algal mats and water-soaked moss; one collected larval specimen was identified using DNA barcoding of two molecular markers, mitochondrial cytochrome oxidase 1 (cox1) and nuclear histone 3 (H3). Larvae of two species, Rygmodus modestus and Rygmodus sp., are described in detail and illustrated; they closely resemble ambush-type predatory larvae of the hydrophilid tribe Hydrophilini in the head morphology. Rygmodus is the only known hydrophilid beetle with adults and larvae inhabiting different environments. [ABSTRACT FROM AUTHOR]

The systematics and the phylogenetic position of the Caribbean representatives of Phaenonotum Sharp (Coleoptera: Hydrophilidae) are investigated to understand the composition of the Caribbean fauna and its origin. Phylogenetic analysis based on mitochondrial and nuclear genes has revealed the Caribbean species to be situated in three deeply nested clades, inferring multiple colonization of Caribbean islands from the continent. Time-tree analysis and BioGeoBEARS analyses of ancestral ranges estimated the oldest clade, consisting of wingless single-island endemics of Cuba (P. delgadoi), Jamaica (P. ondreji sp. nov.) and Hispaniola (P. laterale sp. nov.), to have diverged c. 46.6 Mya from the South American ancestor and subsequently colonizing the Caribbean most likely via the GAARlandia land bridge connecting South America with the Greater Antilles. The remaining three Caribbean species, including the Puerto Rican endemic, P. borinquenum sp. nov., are of more recent (Miocene to Pliocene) origin and colonized the Greater Antilles by over-water dispersal. All the Caribbean species are illustrated and diagnosed, and three new species are described. The genus Phaenonotum, excluding P. caribense Archangelsky, is confirmed as a monophylum. We demonstrate that species-level taxonomy of Phaenonotum is difficult to solve by morphology alone and ideally requires the combination of morphology and molecular markers. [ABSTRACT FROM AUTHOR]

The representatives of the genus Cercyon Leach occurring in the Greater Antilles are reviewed. Ten species are recorded, of which five are described here as new: C. gimmeli sp. n. (Dominican Republic), C. armatipenis sp. n. (Dominican Republic), C. taino sp. n. (Dominican Republic), C. sklodowskae sp. n. (Jamaica) and C. spiniventris sp. n. (Dominican Republic). Diagnoses and detailed distributional data are also provided for C. floridanus Horn, 1890 (distributed in southeastern United States of America and Cayman Islands), C. insularis Chevrolat, 1863 (endemic to the Antilles), C. praetextatus (Say, 1825) (widely distributed in the New World incl. Greater Antilles), C. quisquilius (Linnaeus, 1761) (an adventive species of Paleartic origin) and C. nigriceps (Marshall, 1802) (an adventive species probably of Oriental origin). Cercyon armatipenis, C. gimmeli, C. taino form a group of closely related species only distinguishable by male genitalia and DNA sequences. A key to the Great Antillean Cercyon is provided and important diagnostic characters are illustrated. The larvae of C. insularis and C. taino were associated with adults using COI barcode sequences, illustrated and diagnosed. Full occurrence data, additional images and COI barcode sequences were submitted to open access on-line depositories in an effort to provide access to complete data. [ABSTRACT FROM AUTHOR]

The author refers to the issues faced by researchers while performing molecular dating analyses for beetles focusing on the analyses of beetles from the the Early Permian period to the Late Permian period. The author talks about developments in molecular dating analyses that investigates the effects of fossil selection and estimation of divergence times. The author compares their research with an original chronogram and their analysis.

India and Madagascar drifted apart more than 80 Mya, yet few taxonomic groups currently found in these regions bear any signature of this split. When drifting in isolation, extensive volcanic activity covered almost half of India in lava flows, likely triggering widespread extinction on the island. Consequently, most of India's rich extant flora and fauna are considered to be the result of recent Cenozoic dispersal, and no lineages are conclusively a result of ancient vicariance. Many of Madagascar's lineages also stem from either Cenozoic diversification or dispersal events, with the latter being a result of the close proximity of the island with mainland Africa. In the present study, we focus on two remarkable lineages of cascade beetles in the genera Scoliopsis and Tritonus (Coleoptera, Hydrophilidae), respectively, dwelling in the mountains of south India and Sri Lanka, as well as in Madagascar. Based on a molecular phylogeny of the family Hydrophilidae dated with eight fossils, we show that these two lineages are sister taxa, and diverged when Madagascar and Greater India (India, Sri Lanka, Seychelles) separated, suggesting a pattern of Gondwanean vicariance. The results of the present study show that, despite geological upheaval, the present-day fauna of India still retains traces of its Gondwanan past. [ABSTRACT FROM AUTHOR]

A new species of the genus Elocomosta Hansen, 1989 (Coleoptera: Hydrophilidae: Sphaeridiinae: Coelostomatini), E. lilizheni sp. n., is described from Guangxi Province, China. It is compared in detail with the only other known species of the genus, E. nigra Hansen, 1989 from Borneo, and the genus is diagnosed from the remaining coelostomatine genera. The new species is unusual among Hydrophilidae by having extremely reduced eyes. [ABSTRACT FROM AUTHOR]

The morphology and head chaetotaxy of third instar larva of the endemic CubanB. chevrolatiZaitzev, 1908 are described. We provided the diagnosis of third instar larvae ofB. exiguus(Say, 1825) andB. cf. undatus(Fabricius, 1792). This study is based on specimens collected in Cuba and identified by associations with adults. Larvae ofB. exiguusandB. cf.undatusagree well with previously described larvae ofBerosus. In contrast,B. chevrolatirepresents an unusual morphotype, characterised by narrow and strongly projecting nasale and well-developed right epistomal lobe. We also revise the adult diagnosis ofB. undatus, which was incorrectly provided by Deler-Hernández, Fikáček, and Cala-Riquelme (2013), and provide additional characters to distinguish this species fromB. interstitialisKnisch, 1924 andB.infuscatusLeConte, 1855. [ABSTRACT FROM PUBLISHER]

In order to understand the identity of the Central American species of the genus Phaenonotum Sharp, 1882, the type specimens of the species described by Sharp (1882) deposited in the David Sharp collection in the Natural History Museum in London have been re-examined. The following species are redescribed: Phaenonotum apicale Sharp, 1882, P. collare Sharp, 1882, P. dubium Sharp, 1882 (confirmed as junior synonym of P. exstriatum (Say, 1835)), P. laevicolle Sharp, 1882, P. rotundulum Sharp, 1882 and P. tarsale Sharp, 1882. Lectotypes are designated for P. apicale, P. collare, P. rotundulum and P. tarsale. External diagnostic characters and morphology of male genitalia are illustrated. A table summarizing diagnostic characters allowing the identification of the species is provided. [ABSTRACT FROM AUTHOR]

A new Oriental species of the genus Sphaeridium Fabricius, 1775, S. daemonicum sp. nov., is described based on specimens recently collected in the Brahmaputra valley (lowland part of Arunachal Pradesh, India) and historical specimens from southern Myanmar. The new species differs from all other described Oriental species by its wide parameres partly enveloping the median lobe, small body size, and coloration of the body. It is unique among Oriental species by the presence of a series of small spines along the lateral margin of pronotum and elytra. In the latter character, it resembles the members of the Afrotropical S. simplicipes group. [ABSTRACT FROM AUTHOR]

The occurrence of Pachysternum capense (Mulsant, 1844) (Coleoptera: Hydrophilidae: Megasternini) outside its native range in sub-Saharan Africa and its first records from Brasil, western Australia, Madeira, Romania, and Hungary are summarized. Current distribution data indicate that the species is mainly introduced to coastal areas by shipping and that it underwent several independent introductions to Europe. Pachysternum capense is now well-established in Europe and spread from coastal areas to inlands, with the northernmost record nearly reaching the latitude of 47°N. Multiple records are also known from Canary Island and Western Australia. Based on these data, P. capense has recently became a world-wide adventive species. [ABSTRACT FROM AUTHOR]